THEOREM 7. IfK is reducible to L and K' to L', then K 0 L is reducible to K' 0 L'. THEOREM 8. For a direct sum I1 + 112 of abelian groups H1 and II2, A0(H11 + II2) is reducible to A0(1) 0 A0(II2). Together with Theorem 2 and the results for cyclic groups, these Theorems prove THEOREM 9. If 11 is a finitely generated abelian group, then any abelian homology or cohomology group A,(II) or Af(II, J...